UUID / GUID Validator

What the checker accepts

A token is trimmed. A matching pair of braces is removed and remembered. A urn:uuid: prefix, in either case, is removed and remembered, and braces inside that prefix are handled the same way. What remains must be hex. If it contains hyphens, they must fall in the 8-4-4-4-12 groups. If it contains none, it must be 32 hex digits. Uppercase hex is accepted and does not change the version. The verdict quotes the token you pasted, not the stripped form, then a spaced arrow, then the status.

The version is the first hex digit of the third group. 1 is Gregorian time, 2 is DCE security, 3 is MD5 name-based, 4 is random, 5 is SHA-1 name-based, 6 is reordered Gregorian time, 7 is Unix time, and 8 is custom. The variant nibble is the first hex digit of the fourth group. 8 through b is RFC 4122. c and d are Microsoft. A standard id needs version 1 through 8 and one of those two variants. 550e8400-e29b-41d4-a716-446655440000 is Valid (v4, random, RFC 4122). The same value with c in that variant position is Valid (v4, random, Microsoft).

The box and the result lines

The split is any run of whitespace or commas, so a newline, a space, and a comma are the same kind of separator. One bad token does not stop the list. A paste of the version-4 sample, a space, and not-a-uuid produces a valid line and then Invalid: character "n" is not hexadecimal. Empty tokens from a trailing comma are dropped rather than reported. A box that is only spaces produces an empty result, not an error line.

Notes are appended inside the verdict when the spelling was not the plain hyphenated form. Braces add , braces. A URN prefix adds , URN. Thirty-two hex digits with no hyphens add , no hyphens. Those notes do not change the version. Copy output copies every verdict line. There is no control that copies only the valid tokens, and there is no download. The UUID generator draws new version-4 values. It does not validate a list you already have.

When a version check is the job

Use this page when a log, a spreadsheet column, or a ticket contains ids and you need the version and the obvious formatting mistakes. A mix of version 4 and version 7 is visible on the label: random versus Unix time. That is the check. The page does not decode the millisecond prefix inside a version-7 id. The UUID v7 generator has Inspect timestamp for a hyphenated version-7 value with the RFC variant. A ULID is not a UUID and will fail hex or grouping rules here. The ULID generator is the reader for that spelling.

Nil and max are special-cased before the version table. Thirty-two zeros are Valid nil UUID. Thirty-two f digits are Valid max UUID. They are reported as valid sentinels, not as version 0 or version 15. A discussion of when version 4, version 7, or a ULID belongs in a column is in UUID v4 vs UUID v7 vs ULID. This page only classifies the text you pasted.

Braces, missing groups, and the variant nibble

A single brace, or a brace on only one side, is Invalid: unbalanced braces. Hyphens in the wrong places, including a hyphen missing from the first group only, are Invalid: hyphens must divide the UUID into groups of 8, 4, 4, 4, and 12. A short unhyphenated token such as abc is Invalid: expected 32 hexadecimal digits, found 3, with the found count filled in. A non-hex character names that character. The version digit 0 on an otherwise well-formed id is Invalid: version nibble is 0; expected 1–8, except for the all-zero nil sentinel.

Variant digits 0 through 7 are NCS (reserved). Digits e and f are reserved. Those variants fail even when the version digit is 1 through 8, and the message names both the variant label and the version it would have been. Microsoft c and d are accepted, not rejected. The checker does not look the id up in a database, does not test uniqueness, and does not claim the id was minted by a particular library. Two valid lines can still be duplicates of each other. The result will say valid twice.

Rules and limitations

Tokens split on whitespace and commas. Braces, a urn:uuid: prefix, and 32 unhyphenated hex digits are accepted and noted. Versions 1–8 are labeled. RFC 4122 and Microsoft variants pass. NCS and the reserved variant fail.

Nil is 32 zeros. Max is 32 f digits. Both are valid sentinels. One invalid token leaves the rest of the list in place. Copy output copies the verdict lines. There is no download and no timestamp decode.

Common problems

If a UUID you trust was rejected, look for a version digit outside 1–8, a variant nibble of 0–7 or e–f, unbalanced braces, or hyphens that are not 8-4-4-4-12.

If you wanted the creation time of a version-7 id, this page only labels it Unix time. The UUID v7 inspector prints the UTC timestamp.

Frequently asked questions

About this tool

Maintained by Toolbench. For large or deeply nested files, split the input into smaller batches and verify representative results before using them in an import or application. Report reproducible problems through Contact.